Electric heating unit



F. THORNTON, In; ELECTRIC HEATING UNIT.

APPLICATION FILED Dsc. 2.1918.

Patented 1mm, 1921.

FRANK THORNTON, JR., OF IIIANSFIELD, OHIO, ASSIGNOR T TRIO & MANUFACTURING COMPANY, A CORPORATION O WESTINGHOUSE ELEC- OF PENNSYLVANIA.

ELECTRIC HEATING UNIT.

Application filed December 2 To @ZZ whom t may 007200rn:

Be it known that I, FRANK THORNTON, Jr.,

va citizen of the United States, and a resident of Mansfield, in the county of Rich- 5 land and State of Ohio, have invented a new and useful Improvement in Electric Heating Units, of which the following is a specification.

My invention relates to electrical heating units adapted for use in ranges, radiant grills, vertical toaster stoves, air heaters and the like.

rlhe primary object of my invention is to provide a heating unit of such design as to be highly ethcient in operation and compact in structure.

The existing types of radiant heaters, utilized in grills, ranges or the like, consist of wire coils placed in grooves in porcelain blocks, or coils supported by a number of ferrules carried in a metal frame work. In order to reduce the thickness of such. heaters, it is necessary to wind the coils on a mandrel of small diameter, thus involving numerous disadvantages. The coils, being small in diameter, must be quite long to obtain sufhcient heating surface. Furthermore, in order that the heating surface may be distributed over the desired area, the coils must be folded back and forth or laid up in the form of a spiral. Then such coils are employed and are supported in a porcelain block, the necessary grooves are narrow and the supporting lugs which hold the coils in place are, therefore, small and ditlicult to make. In view of this, one object of my invention is to provide a coil of such design that it may be easily conliiied to the available heating area.

.Another Obj ect of my invention is the provision of a'heating coil of suoli design that the supporting frame therefor may be greatly simplified in structure.

A further object of my invention is the construction of a heating unit which shall reduce to a minimum the ineffective heating surface and, consequently, make possible the employment of less wire in obtaining the desired amount of heat.

A still further object of my invention is the provision of a heating unit of such character that little or no skill shall be required in its construction, whereby rapid quantity production will be promoted.

55 With these and other objects in view, my

Specification of Letters Pa ent.

Patented Dec. 27, 1921. ,1918. serial No. 264,936. i

invention will be more fully described, illustilxated. in the drawing, in the several views which like numerals indicate corresponding parts, and then more particularly pointed out in the claims.

J.ln the drawings, Figure l is a plan view or a heating unit constructed in accordance with my invention; F ig. 2 is a sectional view taken along the line H-II of Fig. l; Fie'. 3 is a perspective view of a mandrel sui?- rounded by a coil and illustrates a step in the method of constructing` mv improved heating coil; ig. 4 is a planwvievvvv of a modifiedformof heating unit which embodies my invention; and Fig. 5 is a sectional view, 70 taken substantially along the line V-V of Fig. 4. i

Various heating units may be constructed within the scope of my invention. the design depending, to a certain extent, upon the area in which the unit is to be confined. F or example` the heating unit may be constructed. as shown in l? ig. l, of substantially rectangular shape and comprising a plurality of heating coils disposed iii side-bysioe relation.

The heatingv unit l, shown in Fig. l, may have a fr nie comprising side members 2 and cross bais 3, the material of which the members 2 and 3 are formed being dependent upon the use to which the frame is to be put. For example, the frame may be constructed of fibrous material impregnated with a binder, such as a. phenolic condensation product, and moldedY to shape. though. preferably, some other heat-resisting ina-l terial such. for example, as asbestos lumber or porcelain will usually be employed because less' likely to be iuinriously affected by high temperatures. I

The heating unit l be assembled by first winding a coil l upon a mandrel 5 having, as shown in Fig. 3, substantially flat, parallel sides. The coil may be wound to a suitable length, after which the mandrel 5 100 may be removed therefrom, or a series of connected coils may be formed upon a single mandrel, provided its length is sufficient, or upon a set of mandrels located in side-bvside or in end-to-eiid relation.

The frame, constituting the support for the various coils, may then be assembled by placing corresponding ends of the cross bars S in the respective recesses provided therefor in one of the side members 2 and securing 110 them in place by screws 6. The coils .4, formed as described, may then be placed in side-byside relation and their rounded portions 7 slipped into the grooves 8 in the members 3. If separate coils are assembled in the manner above specified, the free ends of some of them may be threaded through holes 9 in the cross bars 3 and be joined to corresponding ends of adjacent coils by welding or otherwise to form a continuous winding. Y If connected coils are mounted in the supporting frame, they may be separated by cutting the straight portions of the wire and then joining the coil ends, with reference to the holes 9, as above described. The remaining side member 2 may then be placed in position and be secured to the cross bais 3 by screws 6. In case a connected set of coils is employed, the unit may be assembled by providing the members 3 with open slots into which the straight portions of the coils may be inserted without cutting. In fact, open slots may be provided to receive the coil ends in every case, if desired.

After the coils are thus assembled, the free ends of the end coils are threaded through holes 9 iii one of the members 2 and are secured to suit-able terminals 10 with which the member 2 is provided. It is ob# vious that a single unit, comprising one coil and supporting members, such as described, may be employed, if desired. The frame members, in this instance, may all be secured in place, with the exception of one end member, similar to the member 2 shown in Fig. 1, which may be finally placed Vin position after the coil has been slipped into the supporting grooves provided in side members similar to the members 3.

A modified form of heater unit may be constructed in accordance with my invention, as shown in Fig. 4. The heater unit 11, heie shown, comprises a plurality of concentric frame members 12 having face grooves 13v to receive the rounded edge portions of coils 14. 'Ihe interior and exterior supporting members 12 are provided with grooves in one side only, while the remaining member 12 has grooves provided in both its exterior and interior faces.

rlhe coils 14 may be wound in the manner already described and illustrated in Fig. 3 and` after being wound, may be bent into substantially annular form. The coils 14, after being wound and bent to the desired shape, may be placed in the frame members 12 by forcing their edge portions `into the face grooves 13, the wire having suiiicient two forms of heating unit which vembody my invention, it is obvious that, with minor changes in construction, various forms of heating units may be constructed in accordance with my invention, and I desire, therefore, that no limitations shall be imposed except such as are indicated in the appended claims.

I claim as my invention:

1'. An electric heating unit comprising a helically wound coil having fiat substantially parallel sides and rounded edge portions and a relatively narrow insulating sup-` port therefor engaging said rounded portions externally, the coils being otherwise open to permit of a free circulation of air.

2. An electric heating unit comp 1ising a helically wound coil having fiat substantially parallel sides and rounded edge portions and a relatively narrow insulating support therefor having grooved faces adapted to receive the rounded edge portions, the coils being otherwise open to permit of a free circulation of air.

8. An electric heating unit comprising a plurality of helically wound coils having substantially parallel sides and rounded edge portions disposed in side-by-side relation and a relatively narrow insulating support therefor having grooved faces adapted to receive the rounded edge portions of the respective coils, the coils being otherwise open to permit of a free circulation of air.

4. An electric heating unit comprising a plurality of circular helically wound coils having substantially parallel sides and rounded edge portions concentrically disposed and aielatively narrow insulating support therefor securing the coils Vin spaced relation, the coils being otherwise open to permit of a free circulation of air.

In testimony whereof, I have hereunto subscribed my name this 23rd day of November, 1918.

FRANK THCRNTON, JR. 

